Fire Rainbow Appeared over Singapore

22.02.2017

Residents of Singapore were able to admire the rare natural phenomenon – fire rainbow. At first a small orange circle has appeared in the clouds, which some took for a UFO. Then the other colors of the spectrum were revealed. The celestial show lasted for about 15 minutes.

Fire rainbow, or horizontal arc, is a type of halo. This optical effect in the atmosphere is very rare as its occurrence requires the coincidence of a number of conditions. The altitude of the Sun needs to be more than 58 degrees above the horizon, the sky must have Cirrus clouds and ice crystals in them should have a hexagonal shape and be positioned horizontally. The sun's rays thus pass through the vertical side wall of the crystal and come out of the lower horizontal. As a result, the cloud literally lights.